/* This file is part of swapper project
 *
 * Copyright (C) 2020 The Swapper Project Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package com.swapper.reflect.creator;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public final class UnsafeCreator {
  private static final Object UNSAFE;
  private static final Method ALLOCATE_INSTANCE;

  static {
    try {
      Class<?> unsafeClass = Class.forName("sun.misc.Unsafe");
      Field theUnsafe = unsafeClass.getDeclaredField("theUnsafe");
      theUnsafe.setAccessible(true);
      UNSAFE = theUnsafe.get(null);
      ALLOCATE_INSTANCE = unsafeClass.getMethod("allocateInstance", Class.class);
    } catch (Exception e) {
      throw new RuntimeException(e);
    }
  }

  private UnsafeCreator() {
    throw new UnsupportedOperationException(getClass().getSimpleName());
  }

  @SuppressWarnings("unchecked")
  public static <T> T allocateInstance(Class<?> cls)
          throws InvocationTargetException, IllegalAccessException {
    return (T) ALLOCATE_INSTANCE.invoke(UNSAFE, cls);
  }
}
